There is an on-vehicle apparatus control system in which control of an on-vehicle apparatus is performed, such as locking and unlocking of a door of a vehicle on the basis of radio signals which are transmitted and received between an on-vehicle control device mounted on the vehicle and a portable machine carried by a user. Communication methods between the on-vehicle control device and the portable machine are roughly classified into three methods such as a polling method, a passive entry method, and a keyless entry method.
In the polling method, the on-vehicle control device transmits a response request signal at a predetermined cycle regardless of a position of the portable machine. If the response request signal is received, the portable machine returns a response signal to the on-vehicle control device. In the passive entry method, for example, when a user comes close to or comes into contact with a door knob of a vehicle, a passive request switch provided on the vehicle is turned on, and the on-vehicle control device transmits a response request signal to the portable machine. If the response request signal is received, the portable machine returns a response signal to the on-vehicle control device. In the keyless entry method, a response request signal is not transmitted from the on-vehicle control device to the portable machine, and, when the user operates the portable machine, a remote control signal is transmitted to the on-vehicle control device from the portable machine. In any case, if the response signal or the remote control signal is received from the portable machine, the on-vehicle control device performs collation of an ID code included in the signal. If the collation is successful, the on-vehicle control device locks or unlocks a door of the vehicle.
In a case of the polling method or the passive entry method, for example, illegal communication may be performed in which the portable machine which is far away imitates a state of being in close proximity to a vehicle as a result of a relay relaying a response request signal transmitted from the on-vehicle control device and the portable machine receiving the response request signal. The illegal communication using the relay is called relay attack. A malicious third party who is not an owner of a vehicle may commit a crime such as theft of the vehicle by unlocking a door of the vehicle or starting an engine through the relay attack.
Therefore, regarding crime prevention countermeasures against the relay attack, for example, in JP-A-2003-13644, in the passive entry method, an on-vehicle control device (on-vehicle receiver) measures a period of time from transmission of a response request signal to reception of a response signal with clocking means. Only in a case where a clocked value in the clocking means is within an effective clocked value set in advance when the response signal is received, the response signal is recognized as a normal response signal, and thus a door of a vehicle is locked or unlocked.
In JP-A-2008-45374, a portable machine can select a full mode in which an operation of receiving a polling type response request signal is continuously performed or a power saving mode in which the reception operation is stopped on the basis of an operation on an operation unit of the portable machine or a special command transmitted from a dedicated tool.
In JP-A-2002-247656, a portable machine can select a permission mode in which a response signal to a polling type response request signal is permitted to be transmitted or a prohibition mode in which transmission of the response signal is prohibited on the basis of an operation on an operation switch of the portable machine. The portable machine notifies a user of the present mode through lighting of an LED on the basis of the operation on the operation switch.
As in JP-A-2003-13644, JP-A-2008-45374, and JP-A-2002-247656, in the related art, in a case where relay attack is performed, a door is not locked or unlocked by restricting communication of or a process in the portable machine or the on-vehicle control device.